反应详情

Methyl 3-bromo-4-oxo-6-phenyl-4H-pyran-2-carboxylate (587 g) was added to a stirred solution of dry sodium iodide (315 g) in dry methyl ethyl ketone (8 l). The solution was heated under reflux for 5 minutes, then pyridine (152 ml) was added and heating was continued for 31/2 hours. The mixture was cooled, the solid product was dissolved in water (2 l) and the solution was washed with dichloromethane and filtered. The filtrate was diluted to 10 l and acidified with 5 M hydrochloric acid (760 ml) to precipitate the title product (mp 247° C. with decomposition).

1. temperatureThe solution was heated
2. temperatureunder reflux for 5 minutes
3. temperatureheating
4. custom2 hours
5. temperatureThe mixture was cooled
6. washthe solution was washed with dichloromethane
7. filtrationfiltered
8. additionThe filtrate was diluted to 10 l
9. customto precipitate the title product (mp 247° C. with decomposition)